/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.nexmark.queries;



import com.bff.gaia.unified.sdk.nexmark.NexmarkConfiguration;

import com.bff.gaia.unified.sdk.nexmark.model.Bid;

import com.bff.gaia.unified.sdk.nexmark.model.BidsPerSession;

import com.bff.gaia.unified.sdk.nexmark.model.Event;

import com.bff.gaia.unified.sdk.transforms.Count;

import com.bff.gaia.unified.sdk.transforms.DoFn;

import com.bff.gaia.unified.sdk.transforms.ParDo;

import com.bff.gaia.unified.sdk.transforms.windowing.AfterPane;

import com.bff.gaia.unified.sdk.transforms.windowing.Repeatedly;

import com.bff.gaia.unified.sdk.transforms.windowing.Sessions;

import com.bff.gaia.unified.sdk.transforms.windowing.Window;

import com.bff.gaia.unified.sdk.values.KV;

import com.bff.gaia.unified.sdk.values.PCollection;

import org.joda.time.Duration;



/**

 * Query "11", 'User sessions' (Not in original suite.)

 *

 * <p>Group bids by the same user into sessions with {@code windowSizeSec} max gap. However limit

 * the session to at most {@code maxLogEvents}. Emit the number of bids per session.

 */

public class Query11 extends NexmarkQueryTransform<BidsPerSession> {

  private final NexmarkConfiguration configuration;



  public Query11(NexmarkConfiguration configuration) {

    super("Query11");

    this.configuration = configuration;

  }



  @Override

  public PCollection<BidsPerSession> expand(PCollection<Event> events) {

    PCollection<Long> bidders =

        events

            .apply(NexmarkQueryUtil.JUST_BIDS)

            .apply(

                name + ".Rekey",

                ParDo.of(

                    new DoFn<Bid, Long>() {



                      @ProcessElement

                      public void processElement(ProcessContext c) {

                        Bid bid = c.element();

                        c.output(bid.bidder);

                      }

                    }));



    PCollection<Long> biddersWindowed =

        bidders.apply(

            Window.<Long>into(

                    Sessions.withGapDuration(Duration.standardSeconds(configuration.windowSizeSec)))

                .triggering(

                    Repeatedly.forever(AfterPane.elementCountAtLeast(configuration.maxLogEvents)))

                .discardingFiredPanes()

                .withAllowedLateness(

                    Duration.standardSeconds(configuration.occasionalDelaySec / 2)));

    return biddersWindowed

        .apply(Count.perElement())

        .apply(

            name + ".ToResult",

            ParDo.of(

                new DoFn<KV<Long, Long>, BidsPerSession>() {



                  @ProcessElement

                  public void processElement(ProcessContext c) {

                    c.output(new BidsPerSession(c.element().getKey(), c.element().getValue()));

                  }

                }));

  }

}